【简答题】Choose the correct words to complete the sentences. 1. Researchers often animals in order to learn about their behavior. 2. A spacesuit is when astronauts walk in space. 3. Scientists look for planets...
【简答题】You need to read the (instruct) carefully before you use the machine. 2. The police found out about the deaths of the three men (accident). 3. The (rare) of air on a high mountain is bad for people wi...